Global niche of marine anaerobic metabolisms expanded by particle microenvironments
Global niche of marine anaerobic metabolisms expanded by particle microenvironments
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DOI：
10.1038/s41561-018-0081-0
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发表时间：
2018-04-01
影响因子：
18.3
通讯作者：
Deutsch, Curtis
中科院分区：
文献类型：
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作者：
Bianchi, Daniele;Weber, Thomas S.;Deutsch, Curtis
在海水中，厌氧微生物呼吸应限于沿海地区和热带氧气最低限度地带的缺氧水域，在这些水域中，厌氧微生物呼吸对能量有利。然而，最近的分子和地球化学证据表明，反硝化和硫酸盐还原微生物的分布要广泛得多。厌氧代谢被认为在下沉的有机聚集体内发育的微环境中蓬勃发展，但对这些微环境的全球分布和地球化学意义知之甚少。在这里，我们开发了一个新的尺寸分辨颗粒模型来根据聚集体的性质和海水化学来预测无氧呼吸。受下沉颗粒尺寸谱观测的约束，该模型预测，反硝化和硫酸盐还原可以在广阔的低氧海洋中持续进行，并可以解释硫化物沉淀在颗粒中观察到的微量金属富集物。在全球范围内，与仅基于缺氧区的估计相比，颗粒微环境导致的厌氧生态位的扩大使水柱反硝化的速度翻了一番，并改变了海洋氮循环对气候变暖中脱氧的敏感性。
In ocean waters, anaerobic microbial respiration should be confined to the anoxic waters found in coastal regions and tropical oxygen minimum zones, where it is energetically favourable. However, recent molecular and geochemical evidence has pointed to a much broader distribution of denitrifying and sulfate-reducing microbes. Anaerobic metabolisms are thought to thrive in microenvironments that develop inside sinking organic aggregates, but the global distribution and geochemical significance of these microenvironments is poorly understood. Here, we develop a new size-resolved particle model to predict anaerobic respiration from aggregate properties and seawater chemistry. Constrained by observations of the size spectrum of sinking particles, the model predicts that denitrification and sulfate reduction can be sustained throughout vast, hypoxic expanses of the ocean, and could explain the trace metal enrichment observed in particles due to sulfide precipitation. Globally, the expansion of the anaerobic niche due to particle microenvironments doubles the rate of water column denitrification compared with estimates based on anoxic zones alone, and changes the sensitivity of the marine nitrogen cycle to deoxygenation in a warming climate.